R-448A / Solstice N40 (commercial, zeotropic)
R-448A PT Chart
The full R-448A pressure-temperature reference table, from -30 to 130°F, with both the bubble and dew columns its 7.1 to 10.9°F glide requires. Use the dew point for superheat and the bubble point for subcooling. Checked cell by cell against 3 other published tables, 1 of them a separate publisher: Arkema, Honeywell and CoolProp. One of them, Arkema, has a full column on file here, so this chart prints where that table and ours disagree at every pressure instead of quietly picking one. The widest gap on the bubble column, which is the one compared here, is 0.19 degrees F, against Arkema, at 118 psig.
R-448A Pressure-Temperature Table
| R-448A | |||
|---|---|---|---|
| Pressure (psig) | Bubble °F (subcooling) | Dew °F (superheat) | Publisher spread (°F) |
| 10.4 | -30°F | -19.1°F | 0 |
| 13.5 | -25°F | -14.3°F | 0 |
| 17 | -20°F | -9.2°F | 0 |
| 20.8 | -15°F | -4.3°F | 0 |
| 24.9 | -10°F | 0.7°F | 0 |
| 29.3 | -5°F | 5.5°F | 0.11 |
| 34.2 | 0°F | 10.6°F | 0 |
| 39.4 | 5°F | 15.4°F | 0 |
| 45.1 | 10°F | 20.4°F | 0 |
| 51.2 | 15°F | 25.4°F | 0 |
| 57.8 | 20°F | 30.4°F | 0 |
| 64.8 | 25°F | 35.3°F | 0 |
| 72.3 | 30°F | 40.1°F | 0 |
| 80.4 | 35°F | 45.1°F | 0 |
| 89 | 40°F | 50°F | 0 |
| 98.2 | 45°F | 54.9°F | 0 |
| 108 | 50°F | 60°F | 0 |
| 118 | 55°F | 64.5°F | 0.19 |
| 129 | 60°F | 69.5°F | 0.18 |
| 141 | 65°F | 74.6°F | 0.04 |
| 154 | 70°F | 79.6°F | 0.19 |
| 167 | 75°F | 84.3°F | 0.14 |
| 181 | 80°F | 89.3°F | 0.17 |
| 195 | 85°F | 94°F | 0.03 |
| 211 | 90°F | 99.1°F | 0.15 |
| 227 | 95°F | 103.8°F | 0.09 |
| 244 | 100°F | 108.6°F | 0.08 |
| 262 | 105°F | 113.4°F | 0.08 |
| 281 | 110°F | 118.3°F | 0.13 |
| 300 | 115°F | 122.9°F | 0.05 |
| 321 | 120°F | 127.7°F | 0.02 |
| 343 | 125°F | 132.5°F | 0.09 |
| 365 | 130°F | 137.1°F | 0.07 |
About the spread column. It is the widest gap in saturation temperature between the published tables we hold, at that pressure, on the bubble column. Across this chart the widest is 0.19°F, at 118 psig. Our table and 1 other published table are compared here: 1 is a separate publisher. A narrow spread means the charts agree, which is not the same as the charts being right: they are all computed from equations of state fitted to lab data, and no field measurement settles it.
- Checked against Arkema Forane, all 33 shipped bubble cells within 0.5 psig, and all 33 dew points within 0.2 F [separate publisher]
- Checked against Honeywell Solstice N40, agrees [same model]
- Checked against CoolProp reference data, agrees [same model]
A separate publisher can catch a transcription, edition or rounding error. A cross-check marked same model resolves to the same equation of state as the base table, so it is a consistency check rather than independent confirmation. One marked same printing prints numbers identical to another table listed here, so the two are one witness and we do not count them twice. Sources last re-verified 2026-08-25.
Read the low-side (suction) pressure and its dew temperature for superheat, and the high-side (liquid) pressure and its bubble temperature for subcooling. The chart is in psig (gauge) and °F. To convert: kPa gauge = psig × 6.895; °C = (°F − 32) / 1.8.
R-448A PT Chart FAQs
What is the R-448A pressure at a 40F bubble point?
On the R-448A PT chart, a 40F bubble point corresponds to about 89 psig, where the dew point is 50F. At 211 psig the bubble point is 90F and the dew point is 99.1F. R-448A (Honeywell Solstice N40) is a zeotropic R-404A and R-22 replacement for commercial refrigeration, with a wide 7.1 to 10.9F glide.
Why does the R-448A PT chart have two temperature columns?
R-448A is a zeotropic blend, so at any given pressure it boils and condenses across a range of temperatures rather than at one point. The lower temperature is the bubble point and the higher one is the dew point; the gap is the glide, about 7.1 to 10.9 degrees F for R-448A, wider than most comfort-cooling refrigerants. The chart lists both columns so you read the correct one for each measurement.
Do I use bubble or dew point for R-448A superheat and subcooling?
Use the dew point for superheat and the bubble point for subcooling. Superheat is measured on the suction line where the refrigerant is fully vapor, which is the dew side. Subcooling is measured on the liquid line where it is fully liquid, which is the bubble side. Because R-448A glides 7.1 to 10.9 degrees F, using the wrong column introduces a large error, enough to misdiagnose a commercial rack charge.
What units is this R-448A PT chart in, and how do I convert to kPa or Celsius?
The table is in psig (gauge pressure) and degrees Fahrenheit, the field-standard units in North America. To convert pressure to kPa (gauge), multiply psig by 6.895. To convert temperature to Celsius, use C = (F - 32) / 1.8.
Related HVAC Tools
Superheat & Subcooling Calculator
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The Opteon XP40 alternative commercial blend, with its own bubble and dew columns.
R-404A PT Chart
The refrigerant R-448A replaces, read on a single saturation column.
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